Backyard Aquaponics
A place to discuss aquaponics

I currently have a 4000l main tank and 1000l sump tank together with 4 BYAP beds with 600l of media in each and a 300l hotbed propagating tray. Having just installed 6 half blue barrels I ran into a problem, i should have foreseen but in the excitement of the expansion did not consider it well enough. That is the amount of water that is drawn from my tank during each F&D cycle. Having purchased a bigger pump (Hozelock 12000l/hr) to deal with the increased flow (and head) necessary for the expansion I found that the tank dropped so much I was worried that any future expansion would be limited.
When I was at BYAP, Nat kept telling me all about the blue barrels and making my head spin - I now have 6 blue barrels and counting. He also suggested that I should consider a split system (ie 2 completely separate systems) rather than a big system with a sump. The problem for me with 2 separate systems is the nitrates. i need all the growing space I can get to deal with the nitrates produced by the trout of winter and the Silvers over summer. While I see the benefit in the 2 separate systems, especially eliminating the 12v pump and float switches which are a pain, I was not convinced that it would work for me with my nitrate problem.
Nat does get you thinking, so his 2 system suggestion kept nagging me in the back of my mind; a solution had to be in there somewhere (Thank god he does not sell life insurance or time share or I would be poor; you're a bloody legend Nat).
Ultimately I would like to have 5 BYAP grow beds (currently have 4), 1 smaller bed (old hot bed - currently in place) and 8 to 10 blue barrels (currently have 6 half barrels) as well as replace my 1000l sump tank (used for trout) with a 3000l tank. Put the trout in the 4000l tank and the silvers in the 3000l. I also wanted to be a little more energy efficient and to reduce possible points of failure. I was thinking that 2 pumps running were better than 1 pump with one in the shed in case of failure and removing the need to pump the water back to the main tank, particularly when there is a power failure and you need a 12v backup pump and float valve, could only be an improvement.

Soooo, I came up with the following concept. I would be interested in your thoughts on it. See attached diagram. (excuse the rough hastily thrown together diagram)

In summary
- the site is not level and slopes down from right to left.
- Tanks 1 and 2 are partially buried in the ground.
- a pump in each tank
- water from tank 1 is pumped to GB 4 and 5 and the blue barrels (the top of the beds to the top of the water surface is over a metre)
- These beds drain to tank 2
- Water from Tank 2 is pumped to GB 1, 2, 3 and 6
- These beds drain to tank 1
- both pumps on the same timer, running flood and drain
- any excess water in any of the 2 tanks can move from one to the other by way of a 50mm joining pipe.
- the water remains mixed and consistent between both tanks.
- all return pipes have a barrel union just prior to entering the tanks so water can be directed to an alternate tank if needed. This would also allow the systems to be run separately if needed.
- the 2 pumps have a total wattage of 130w - current single pump wattage is 130w (Hozelock 12000)
- no other pumps required (350w sump pump and float valve eliminated along with the 12v backup sump pump and float valve)
- backup system consists of 12v air pump and spray bar to both tanks with the pump in one of the tanks, allowing ammonia, O2 to be distributed across both tanks.
- if one pump fails then fish have a better chance of surviving than if a single pump fails. Also the remaining pump can still deal with ammonia and keep the bed bacteria alive (at least for half of the beds) while a new pump is sought.
- allows for even more expansion - unlikely but possible.
- I'm not sure if there will be a solids issue, particularly for trout if all their water is going into half the beds. But then for 4 months of the year there will be no solids going into the beds to allow the worms etc to deal with it.

What are your thoughts on this approach to a 2 tank, 2 pumps joined system?

I think 2 systems would be better. Will you use a screen on the pipe to stop fish going between the tanks - if so what happens if the screen clogs (eg any mismatch in flow may end up transferring water and overflowing one side of the system)?

What height will the join in the tanks be ? Having two pumps in the system is good for reliability, though what happens if you have a leak/blockage - will it compromise both systems?

Don't think these concerns are show stoppers - just need mitigating. Another option could be sequencing valves?

I too have been thinking about a split system, chift pist though, wondering pros and cons. I notice that all your water is rotated thru each component, or going thru 2 ft's and 2 sets of gb's in a complete cycle. If there is a leak in the system wouldn't it mt both ft's? If a pump failed would 1 tank overflow and 1 mt?
Curse my constantly morphing plan.

Thanks mattyoga for your comments
yes I will use a screen. Not much chance of clogging as tanks are in a greenhouse and checked twice a day or more (feeding times)

Joining pipe will be about 15cm from the top of the tank (Maybe less).
If there is a leak or blockage water can only fall to the level of the float valve and only in 1 tank (same problem exists with current/separate systems)
I have not heard great reports about sequencing valves. If they were reliable and worked well would there not be more use of them.

As the joining pipe is only 15cm from the top it would not allow both tanks to empty. Also I have float valves so pumps would shut off if the water dropped below a certain level - that problem exists with current systems, big or small unless steps are taken to mitigate it such as float valves.
Yes if one pump failed the water returning to that tank would not be able to move fast enough to the other tanks as the pipe would be too small and some water would overflow before the float valve shut the other pump off. IMO that is a small price to pay for the advantages - also that problem exists with a sump tank system


you are lucky it is still a plan it is so much more challenging if you have a system and you are expanding

Bloody Nat! Glad I dont live near Jandakot or otherwise I would have a yard full of blue barrels. Im sure he gets a cut or something lol

If it was me i would do 4 beds on tank 1 and the other 2 beds and the barrels on tank 2 if that is how the site slopes and keep them 2 separate systems

Sent from my GT-I9100T using Tapatalk 2

Hi Nat.
I get where you are coming from but it does not assist with my nitrate problem. if i run it as two separate systems i will have to grow less trout than before (30-35kg) and so would defeat the purpose of the upgrade.

To my mind the main advantage of 2 separate systems would be disease control. At the moment the high nitrates would be the most likley cause of diseases in the system and so i think addressing that aspect is the priority.

if i can sort out the nitrate issue (eg put some dwc or nft in) i can easily swap to 2 separate systems.

How big are your silvers?

There has been evidence of cohabitation with larger silvers. You could run 2 systems then.

Personally i dont see a problem with running them together, any problem can be easily overcome with design.

The silvers are big enough to eat - 400- 600gms (possibly bigger) along with the usual small ones.
What advantages would there be would runnng two separate systems with both trout and silvers together in each tank?
Getting the trout out of a big tank is hard enough without having silvers to deal with as well.
With the exception of disease control I am struggling to see any significant advantage of 2 separate systems over a 2 tanks- 2 pumps joined system.

The advantage would be spreading your nitrates over 2 systems.

I am with you though, with the exception of disease control, it really is not hard to design out any problems, which you had mostly done with your existing system anyway. The biggest issue would be emptying a tank, which you have covered.

Thanks Ryan, I was struggling to see any significant problems and given the feed back so far has been in relation to issues that affect current sump tank setups, I am feeling more confident that it is worth going down this path.

Ah now I see where you were coming from . yep that would do the trick but I think I would rather put a 5000l tank in and run it as one system with a sump - any excuse to get bigger tanks .

Now you are talking mate

If you're not going to implement two systems but are going to get a sump, particularly if the sump is going to be larger than (basic figures) :

6 x 600L GBs x 40% water = 1440L
plus
10 x 120L Blue Barrels x 40% = 480L
equals
1920L of water required to simultaneously flood all the beds and barrels,

then you could install a large CHIFT PIST system with a single pump in the ST feeding a distribution manifold to both FTs, which then utilise SLOs to deliver their waste and water to a common distribution manifold for equal dispersal of the flow to each of the GBs and barrels; all water returns to the sump.

The plumbing is simple, the running costs minimised, the second pump can be held in reserve for contingency, allows for further expansion, alleviates your concerns with unbalanced nitrate loads, provides a third tank (ST) but with variable water height which can still be used for fingerlings or another species, the CHIFT PIST design has been proven to work, facilitates the installation of inline filters if you desire/require (they seem to be the flavour of the month atm). ???

I like that idea.

You could make the 2KL tank the constant height tank and the 4KL the sump tank...